In soil irrigation, there is a recognized need to ensure the most uniform distribution of the irrigation liquid delivered by an irrigation apparatus of a fixed or movable system.
Particularly, it is important to avoid excessive liquid supply in certain areas and inadequate liquid supply in other areas.
Furthermore, the liquid jet should reach the soil in an appropriately distributed fashion, and not be excessively concentrated, to prevent soil damages.
Gun-type irrigation apparatus are also known, which have a launch pipe with an internal conduit for delivering a liquid jet, and with a jet supply nozzle at one end.
A jet-breaker device is placed at the nozzle, and has a jet-breaking element which is designed to interfere with the jet to break it, thereby allowing liquid distribution to a larger soil area.
The action of the jet-breaking element allows liquid to reach the soil in a substantially uniform, predetermined concentration.
Thus, liquid will be distributed in a substantially constant fashion, both close to the system and in the remotest areas that can be reached by the jet.
One drawback of this solution is that the action of the jet-breaking element is constant and cannot be adjusted according to the flow rate and range of the nozzle jet.
Due to the continuous interference of the jet-breaking element with the jet, the distribution of liquid to the soil cannot be easily adapted to particular irrigation requirements.
In an attempt to obviate this drawback, various irrigation apparatus with jet-breaker devices have been developed, in which the jet-breaking element is movably connected to the launch pipe and interferes with the jet in a discontinuous manner.
The jet-breaking element is mounted to a bracket that oscillates relative to the launch pipe under the action of the jet on the jet-breaking element.
The jet-breaking element has a cyclic motion, which is caused by the force generated during the interference between the element and the jet.
Therefore, the oscillation frequency of the interference element depends on the jet flow rate and range.
While this configuration allows liquid distribution to be changed according to the flow rate and range, it still suffers from certain drawbacks.
Namely, this solution does not allow the oscillation frequency of the jet-breaking element to be changed when the jet flow rate and range is constant.
This drawback is particularly disadvantageous when a soil portion is to be irrigated with different liquid distributions.
A further drawback of this solution is that low-flow, short-range jets considerably reduce the oscillation stroke of the jet-breaking element, which will not have enough energy to distribute the jet, and will deliver a compact jet for long periods of time.
In this case, a particularly concentrated jet may cause damages to the soil and crops.
This particularly occurs when jet delivery begins, i.e. when common jet-breaker devices cannot prevent the jet from reaching the soil in compact form.